1. Field of the Invention
This invention relates generally to handling of magnetic cards, and more particularly to apparatus for transporting a flat flexible magnetic card past a magnetic head or electro-magnetic transducer and insuring effective low pressure contact between, and accurate alignment of, the card and the head.
2. Description of the Prior Art
Prior magnetic card handling systems generally handle the cards flat and employ a pressure roller or spring-urged pad on the opposite side of the card from the transducer or magnetic head to apply pressure between the latter and the card. While the device of U.S. Pat. No. 3,495,222 employs curved guides 114, 115, such are merely for directing a card 150 manually inserted in the inlet 113 and downwardly into the constantly rotating drive rollers to an outlet 114 conveniently located for the operator, since the card direction of travel is not reversed. That device maintains the magnetic head 129 spring-urged in engagement with the card so that, like the other prior systems, such spring pressure results in excessive wear. Unlike the machine of U.S. Pat. No. 3,495,222, other prior art devices effect reversal of the direction of travel of each card to provide an automatic two stage power driven cycle, such as that of U.S. Pat. No. 3,337,213, with the return path of the card, however, being different than that during its initial movement. In some prior devices proper registration of the magnetic card with the head or transducer is attained by the application of pressure against a longitudinal edge of the card to engage the opposite edge with a guide, as by a spring-urged ball, but that also is a source of excessive wear. In U.S. Pat. No. 3,752,962 card alignment with respect to successively passed, read and write heads in a unidirectional movement is effected by an endless belt for transporting the card that is skewed at an angle to a fixed linear card guide. And another prior device of interest is disclosed in U.S. Pat. No. 3,671,719 which imparts inward and reverse or return movements to a card, although in different paths, and effects edge engagement of the card with a guide by means of resilient cup-shaped rollers having wedge-shaped cuts in their annular peripheries to produce a plurality of radially projecting flexible teeth which engage the card, on its upper surface during inward movement, on its trailing edge to drive the card from one side to the other of its path preparatory to initiation of return or outward card movement, and on the under surface of the card to continue that return after the card movement has been reversed by rebounding of a leaf spring struck by the initially leading edge of the card.